Today we had the fun experience of harvesting sweet potatoes. Here in PA, we aim to harvest them before the first fall frost which is still nearly a month away. We could have waited a few weeks to let the potatoes get a bit bigger, but sometimes we just harvest when you get the itch!

Getting started growing sweet potatoes
Growing sweet potatoes is very easy, but it requires some patience and forethought. We started back in Feb/March during the winter by visiting our local grocery store and selecting a few small sweet potatoes. Next, we place them in mason jars that with water covering about 1/3 of the tuber. To keep the tuber still, we placed large skewers (broken into smaller lengths) like one would use for grilling into the top of the tuber so that the tuber’s weight rested on these skewers keeping the bottom of the tuber off the bottom of the jar. This is because some of the slips that begin to grow do so from the bottom. It’s just a preference of ours.

How long will they take to sprout!?
After several months (like 2-3), we had healthy slips growing from the submersed tubers. It will seem like forever before they start to grow. They might not grow, but give it a chance! About 1-2 weeks before you intend to plant the slips, remove them from the submersed tuber and place them in their own jar of water. They will re-sprout “water roots”. These will be important for getting the plant established.

When to plant outdoors
When the soil is good and warm (sometime in May for us) , mound up some well cultivated soil into a pretty large furrow. You want the mound to be deep enough to allow for some good tuber growth. Make sure the soil is well cultivated. We added a little bit of composted horse manure and also some peet moss as well. Next, cover the mound with black plastic or landscape fabric, then punch 1″ or so holes about every 18″. We only ended up with 6 usable “slips” from the above process, so we spaced ours out a bit more. Use a stick or something similar to drive through the holes in the black plastic/fabric down into the soil a good 12″ or so. Place a slip in each one, then lightly pack the soil back around the slip and water each slip well. Over the growing season, be sure to occasionally side-dress the tubers with some fertilizer (we use fish emulsion). In several weeks, the slips will start to expand and voraciously cover the surrounding area. It will be somewhat invasive at times, so bear this in mind when choosing a location to plant!

How long do they take to grow and how do you harvest?
Most varieties take from 95-110 days to mature. When that much time has elapsed, or just before the first fall frost, pull back some of the black ground cover and paw around the base of one of the plants. You should find some nice-sized tubers!

This is what a cluster of tubers will look like when you start to paw around
This is what a cluster of tubers will look like when you start to paw around

To harvest, remove the top ground cover of the plant, pull back the black ground cover and gently start to paw around where the base of each slip had been planted. You should find collections of 6-10 tubers where each slip had been with occasional tubers in between or at the edges. We use our hands to harvest and it’s something nearly the whole family enjoys. Harvesting tubers is a very kid-friendly thing to do. You’ll want to encourage your children not to pull on the tubers too hard, and not to use tools that will pierce the potatoes. Aside from that, it’s kind of like digging for treasure.

Once harvested, allow to sit for 6-8 hours in the sun, then move indoors to a warm (70-80℉) room for another week or so before placing in storage. Sweet potatoes should hold up well in a cool dry place for the winter (root cellar, garage, basement, etc).

Gotchas!
We found that deer really like to eat the sweet potato greens. See our previous post about deer repellent to read how we prevented this. Also, it’s important to regularly inspect the area surrounding your black ground cover. It’s quite common for burrowing rodents to sneak under their and harvest your tubers for you! Perhaps a cat could help with this task 😉

How about yield?
Only 5 out of our 6 slips survived because one snapped while planting. For each slip planted, we grew approximately 6-10 tubers averaging about 3-4 lbs. of tubers per slip. Next year we’re planning on planting quite a few more slips and planting them closer together which would have given us a higher yield. For our family of five, we grew just about the number of potatoes we’d eat over the winter months. We might use 3-4 tubers in one meal and eat them every other week or so at most, so this is sufficient yield for us. We would prefer to grow about 20-30% more than we require to share with others, account for spoilage, and also to set aside some for next year’s seed.

Our harvest of Sweet Potatoes from 5 slips
Our harvest of Sweet Potatoes from 5 slips

What about the greens?
We’ve read that some people harvest and eat the sweet potato greens as well. Apparently in Japan, their quite common. We’ve never done so. Today, we fed our greens to the chickens to give them some nutritious snacks.